Psychology Team

Jennifer Katzenstein, PhD

Jennifer Katzenstein, PhD

Neuropsychology
Dr. Katzenstein is the director of psychology, neuropsychology and social work, at Johns Hopkins All Children’s Hospital. Previously, Dr. Katzenstein was a private practitioner and Assistant Professor of Neurology at Indiana University School of Medicine/Riley Hospital for Children in Indianapolis where she provided neuropsychological evaluations, consultations and academic coaching for children and adolescents. After graduating from Indiana University Purdue University Indianapolis, she completed a pediatric internship and fellowship at Texas Children's Hospital/Baylor College of Medicine. Dr. Katzenstein is board certified in pediatric neuropsychology and clinical neuropsychology.
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Dianna Boone, PhD

Dianna Boone, PhD

Psychology
Dr. Boone is a pediatric psychologist at Johns Hopkins All Children’s Hospital. She joined the hospital staff in 2022. Dr. Boone sees patients as part of the Healthy Weight Initiative and provides weekly outpatient therapy to patients with weight management concerns. She also provides weekly outpatient therapy to patients with anxiety, depression, and adjustment disorders.
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Sakina Butt, PsyD

Sakina Butt, PsyD

Psychology Neuropsychology
Dr. Butt is a neuropsychologist at Johns Hopkins All Children’s Hospital. She joined the hospital staff in 2019. Some of Dr. Butt’s areas of clinical expertise include neuropsychological evaluations and consultations for children in the neonatal intensive care unit and pediatric intensive care unit.
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Lacy Chavis, PsyD

Lacy Chavis, PsyD

Psychology
Dr. Chavis is a pediatric psychologist in the Johns Hopkins All Children’s Institute for Brain Protection Sciences. She holds specialty certification in evaluation and treatment of perinatal mental health. She provides consultation, evaluation and treatment intervention services on the inpatient units regarding adaptation and coping with illness, treatment adherence, and emotional and behavioral functioning. She joined the hospital staff in 2012. Dr. Chavis received her doctoral degree in clinical psychology from Illinois School of Professional Psychology-Argosy University. She completed a pediatric internship in clinical psychology at New York Center for Child Development with emphasis on early childhood development and trauma. Dr. Chavis continued to specialize with fellowship at Andrus Children’s Center focusing on trauma, parent-child interactions and maternal mental health. Dr. Chavis’ research interests include neurodevelopmental and social-emotional outcomes of premature infants, maternal mental health and the cost-effectiveness of early psychological intervention.
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Melissa Faith, PhD

Melissa Faith, PhD

Psychology
Dr. Faith is a clinical pediatric psychologist specializing in hematology/oncology at Johns Hopkins All Children’s Hospital. She received her master’s and doctorate degrees in clinical psychology from the University of Arkansas, completed a predoctoral internship in clinical child psychology at the University of Mississippi Medical Center and completed a postdoctoral fellowship in clinical psychology with an emphasis in pediatric hematology and oncology at the University of Oklahoma Health Sciences Center. Dr. Faith’s research interests include disseminating evidence-based interventions in large medical and community centers (e.g., motivational interviewing) as well as emotion socialization, social adjustment, and sibling adjustment during and following childhood chronic illness. 
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Marissa Feldman, PhD

Marissa Feldman, PhD

Psychology
Dr. Feldman is a pediatric psychologist in the Johns Hopkins All Children’s Institute for Brain Protection Sciences. She specializes in the evaluation and treatment of children and adolescents with acute and/or chronic medical conditions to promote psychological health and well-being, and provides consultation services on the inpatient units regarding adaptation and coping with illness, treatment adherence, and emotional and behavioral functioning. She joined the hospital staff in 2017. Dr. Feldman received her Doctoral degree in clinical psychology from the University of South Florida, and completed her internship and fellowship at the Ann & Robert H. Lurie Children’s Hospital of Chicago (formerly Children’s Memorial Hospital). Dr. Feldman’s research interests include treatment adherence and quality of life in patients with chronic illness, outcomes of group intervention, psychosocial factors contributing to positive youth development and negative peer relations. 
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William Frye, PhD

William Frye, PhD

Psychology
Dr. Frye is a pediatric psychologist in the Chronic Pain Clinic at Johns Hopkins All Children’s Hospital. He specializes in non-pharmacological treatment for patients with acute and chronic pain conditions and provides skill-based interventions for simultaneous psychosocial concerns. He joined the hospital staff in 2018. Dr. Frye earned his doctoral degree in clinical psychology from Auburn University. He completed a pre-doctoral internship in pediatric psychology at Children’s Mercy Hospitals and Clinics and a postdoctoral fellowship in chronic pain at Nationwide Children’s Hospital. Dr. Frye’s research interests include pain coping and catastrophizing and parental impact on youth outcomes. He is Board Certified in Biofeedback (BCB) by The Association for Applied Psychophysiology and Biofeedback.
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Lauren Gardner, PhD

Lauren Gardner, PhD

Psychology
Dr. Gardner is the psychology internship director and administrative director of the Autism Program at Johns Hopkins All Children’s Hospital. She has provided services for children and families with a wide range of concerns, including noncompliance, autism spectrum disorder, developmental disabilities, depression, anxiety and social skills deficits. Dr. Gardner’s clinical interests include neurodevelopmental disabilities. She earned her doctorate degree from Indiana University Bloomington and completed an internship in psychology at the University of Tennessee Health Science Center and a fellowship in developmental/behavioral pediatrics at the Boling Center for Developmental Disabilities.
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Callie Gilchrest, PhD MEd

Callie Gilchrest, PhD MEd

Psychology
Dr. Gilchrest is a pediatric psychologist who specializes in assessment and treatment of autism and other neurodevelopmental disorders. She primarily works in the autism and developmental pediatrics programs on the Johns Hopkins All Children’s Hospital main campus in St. Petersburg, Florida. She joined the hospital staff in 2022.
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Jason Hangauer, PhD

Jason Hangauer, PhD

Psychology
Dr. Hangauer is a pediatric outpatient psychologist at Johns Hopkins All Children’s Hospital. He specializes in the evaluation and treatment of autism spectrum disorder (ASD) and developmental disabilities. He joined hospital staff in 2018. Dr. Hangauer's research interests include evidence-based interventions for ASD, behavioral parent training, and assisting allied providers serving children with ASD and other disorders in the use of current research supported best practices.
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Colleen Hess, PhD

Colleen Hess, PhD

Psychology
Dr. Hess is a neuropsychologist at Johns Hopkins All Children’s Hospital. She joined the hospital staff in 2021. Her clinical expertise includes neuropsychological evaluations and consultations for children with cancer and brain tumors. Dr. Hess earned her doctoral degree from Florida State University in Tallahassee, Florida. She completed a clinical psychology internship at the University of Florida Health Science Center/Shands Hospital in Gainesville, Florida, followed by a fellowship in clinical psychology at Rothman Center for Pediatric Neuropsychiatry/University of South Florida in St. Petersburg, Florida. Dr. Hess then completed a pediatric neuropsychology fellowship at Johns Hopkins All Children’s Hospital. 
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Aja Meyer, PhD

Aja Meyer, PhD

Psychology
Dr. Meyer earned her doctorate degree from the University of South Florida, and completed an internship at the Children's Hospital of Michigan and a post-doctoral fellowship at Akron Children's Hospital. Dr. Meyer has provided psychological services to children and adolescents with a broad range of medical conditions, such as diabetes, kidney disease, sickle cell anemia, cancer, and various neurological conditions (e.g., AVM, cerebral palsy, chronic pain, epilepsy, spinal cord injury, stroke, and traumatic brain injury). She provides consultation services on the inpatient units at Johns Hopkins All Children's Hospital and sees outpatients as part of the All Children's Pediatric Psychiatry program.
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Jonathan Poquiz, PhD

Jonathan Poquiz, PhD

Psychology
Dr. Poquiz is a pediatric psychologist in the Gender Affirming Care Clinic at Johns Hopkins All Children’s. He joined the hospital staff in 2021. Dr. Poquiz specializes in providing outpatient and interdisciplinary care for transgender and gender diverse youth, as well as for youth with differences in sex development/intersex diagnoses.
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Sarah Sobalvarro, PhD

Sarah Sobalvarro, PhD

Psychology
Dr. Sobalvarro is a pediatric psychologist in the Johns Hopkins All Children’s Institute for Brain Protection Sciences. She joined the hospital staff in 2019. In her role, Dr. Sobalvarro sees patients in the weight management and eating disorder clinics and provides weekly therapy for patients with disordered eating, body dissatisfaction, weight management concerns and psychological conditions.
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Callie King, Ph.D.

Callie King, Ph.D.

Psychology Fellow

Nicholas Smith, Ph.D.

Nicholas Smith, Ph.D.

Psychology Fellow